1. Field of the Invention
The present invention relates to road resurfacing equipment and more particularly to apparatus, systems and methods for recycling a paved surface in situ.
2. Background
Asphalt is the most recycled material in the United States. In fact, more than 73 million tons of asphalt pavement removed each year during highway widening and resurfacing projects is reused as pavement. Such recycling efforts conserve natural resources, decrease construction time, minimize the impact of asphalt plant operations on the environment, and reduce reliance on landfills. Further, research shows that the structural performance of mixtures integrating reclaimed asphalt pavement (“RAP”) is equal to, and in some instances better than, virgin asphalt pavement.
A process for recycling a paved surface may include mechanically breaking up a paved surface, applying fresh asphalt or asphalt rejuvenation materials to the broken pieces, depositing the mixture over the road surface, and compacting the mixture to restore a smooth paved surface. In some cases, broken asphalt may be removed from a road surface, treated off location, and then returned and compacted. By enabling the majority of road surface excavation and renovation to occur through a continuous operation in situ, road recycling processes reduce manpower, time and resources required with conventional road resurfacing techniques.
In some cases, a paved surface may be pre-heated to facilitate pavement removal as well as to increase thermal bonding between new and reclaimed pavement constituents. The low heat conductivity of asphalt and its susceptibility to damage from scorching or overheating, however, creates a dilemma in pavement recycling. In some cases, intense heat must be applied to bring the full depth of the pavement to a workable temperature while the pavement surface must be protected from scorching or overheating.
To overcome this problem, many conventional road recycling processes require heating equipment to make several passes over the same section of roadway in order to heat and work the pavement to a sufficient depth. This procedure is inefficient, time-consuming, and results in most of the heat being concentrated at the pavement surface, as opposed to a uniform distribution through the full depth of the paved surface. Other road recycling processes use multiple heating units that each operate at a temperature below the asphalt burning point. A large number of such units are required to achieve the desired heat penetration, thereby increasing the amount and cost of recycling equipment needed to repair a paved surface
Accordingly, what are needed are improved apparatus, systems, and methods for in situ pavement recycling. More particularly, apparatus, systems, and methods are needed allowing application of higher temperatures to a paved surface in situ, while providing more uniform heat distribution and a reduced likelihood of burning, scorching, or other damage. Beneficially, such a system would improve the bond between new and recycled pavement constituents, reduce the amount of new pavement materials needed to rejuvenate a paved surface, facilitate immediate pavement finishing processes, and increase the structural integrity of the resulting recycled paved surface. Such apparatus, systems, and methods are disclosed and claimed herein.